What are moon phases and why do they exist?
The classic experiment for showing how this works is to use a lamp or flashlight and a ball. The flashlight represents the sun. Put it on a shelf on the opposite side of the room, pointing towards you. Your head represents the earth, and the ball represents the moon. Stand holding the ball up in front of you, and slowly turn around on the spot. Watch how the flashlight shining on the ball is similar to the changing phases of the moon.